1. Field of the Invention
This invention relates to wax emulsions for use in water-proofing or otherwise protecting various materials.
2. Description of the Prior Art
Heretofore, hydrocarbon wax has found extensive application in for example water-proofing a material because it remains to be solid at room temperature, has a definite melting point at relatively low temperatures and is per se hydrophobic. Its application is also intended to provide an improvement in mechanical strength, gloss, smoothness and other protective properties of numerous materials.
Hydrocarbon wax is usually impregnated in or coated on fibrous materials such as wood, paper, yarn and fabric, as well as articles made of plaster, porcelain, cement and the like. It is more recently applied also to fertilizers, agricultural chemicals, medicines and the like. To effect impregnation or coating of the hydrocarbon wax, this is usually heated to melt, dissolved or dispersed in a solvent, or emulsified in water. However, it can be best applied in the form of an emulsion, considering safety, economy and workability.
Although hydrocarbon wax is hydrophobic, its emulsion when coated and dried at room temperature can hardly make the resultant coated surface water-proof. This is because its film-forming temperature is higher than room temperature and hence, it is believed that the coated surface merely has a distribution of discrete hydrocarbon wax particles with interstices permitting passage of water therethrough. An attempt was made to form a continuous film by fusing together such discretely arranged wax particles with heat, but this has not significantly improved water-proofness of the coated surface. It is believed that the film of the coat which appears microscopically to be continuous is still discrete due to the presence of pores, ruptures or interstices of the crystals which develop on account of the hydrocarbon wax being crystalline and fragile and which allow intrusion of water.
Another attempt was made to reduce the film-forming temperature of hydrocarbon wax with use of certain additives. This was quite possible, but such additives were not satisfactory in their own water-resistance or compatibility with the hydrocarbon wax.